1. Field of the Invention
The present invention generally relates to a rotary speed detection method of a rotating shaft of an induction motor and a detection device using the same for detecting the rotary speed of the rotating shaft of the induction motor, a rotational torque detection method of a rotating shaft of an induction motor and a detection device using the same for detecting the rotary torque of the rotating shaft of the induction motor, a reaction liquid viscosity detection method and a reaction liquid viscosity detection device and a manufacturing method of a reaction product.
2. Description of Related Art
Measuring instruments for measuring rotary speed are generally categorized into: contact type (mechanical type) and non-contact type (optical type, electromagnetic type) according to the manner of measurement, digital and analog according to the processing method of the measurement signal, and explosion-proof and non-explosion-proof according to the place of use. Particularly, in the manufacturing sites at which resins, such as urethane, varnish, phenol and the like, are manufactured via chemical reaction, using the explosion-proof measuring instruments is required.
Generally, measuring instruments of rotary speed known as the conventional ones are: handy digital tachometer which includes both contact type and non-contact type (Ono Sokki HT-5500), visible light type takohai tester (Hioki FT3405), electromagnetic rotary measuring instrument (Hioki MP-200), explosion-proof rotary measuring instrument (Ono Sokki RP-200) and the like. These measuring instruments are capable of both high accuracy and safety in use by being appropriately selected based on the type of application.
The application of these rotary speed measuring instruments is widespread, and for example, they are used to measure the rotary speed of the rotating shafts (output shafts) of induction motors.
On the other hand, the inventors of the present invention provide a reaction liquid viscosity detector (Patent Reference 1), wherein an induction motor driven by an inverter is used as a power source and the detector is installed in a reaction vessel which performs the agitating the reaction liquid by rotating a rotational shaft having an agitation blade. The detector includes the following 1) to 5) means, wherein the rotary torque is obtained by using T=(PI −PL)/ω based on the power input (PI), the loss power (PL), and the angular velocity (ω) obtained from the measured values at each measuring instrument, and the detector is characterized in that the reaction liquid viscosity is calculated from the rotary torque.    1) power detection means for measuring the power supplied to the induction motor,    2) current detection means for measuring the current supplied to the induction motor,    3) voltage detection means for measuring the voltage supplied to the induction motor,    4) rotational speed detection means for measuring the speed of the rotational shaft of the induction motor, and    5) frequency detection means for measuring the inverter output frequency.
Patent reference 1: Japan Laid Open Publication No. 2010-190882